Estimated reading time:7 minutes
A variety of factors must be considered in dripper and dripline selection. The designer and/or producer must determine which attributes are necessary for the crop and circumstances. The purpose is to maintain a balance between dripper cost and performance.
Remember, equipment cost is calculated on a sliding scale determined by a host of factors. A comprehensive portfolio of drippers and driplines that cover a wide range of crops and applications is available.
For more information regarding irrigation planning and selection, read the following articles in Netafim’s series:
- Precision planning for precision irrigation
- Drip Irrigation: What you need to know
- Drip irrigation maintenance: What you need to know
- Micro-sprinkler irrigation: What you need to know
- Open-field sprinkler irrigation: What you need to know
- Drip irrigation on maize: Measure and manage for more
Consider a dripline selection graph where the vertical axis is cost and the horizontal axis is a composite of application, durability, clogging resistance and other factors considered in dripper comparison. Movement along the horizontal axis will result in movement along the vertical axis, which represents an increase or decrease in price.
One attribute to consider is wall thickness. The thicker the pipe wall, the more durable the pipe; however, it requires more plastic and increases the expense. A thinner wall thickness will make the dripline much cheaper, but it will potentially have a higher probability of dripline damage.
One aspect of a dripper’s specification is whether it is to be used in heavy, medium or thin wall pipe. Therefore, a large, advanced dripper meant to last a long time will be used in a heavy wall dripline with suitable durability. At the other end of the spectrum, a small dripper will be welded into a thin wall dripline. Small drippers are at greater risk of potentially clogging and are only purposed for a single season.
It all boils down to what crops need. For example, experts will not recommend the same equipment for irrigation with hard, murky water for a single season than for irrigation with the same water where the equipment needs to last many seasons. Similarly, the same equipment will not be used for irrigation with much better water quality.
Thin wall driplines
Thin wall driplines are defined as driplines with a wall thickness of 0,4mm or smaller. These driplines are specifically designed to be used for one to three seasons on vegetables and certain field cash crops. It is also perfectly suited for temporary installation for strip wetting for germination.
Where advanced heavy wall driplines aimed at multi-seasonal use over-cater in terms of crop needs and circumstances, they waste money and labour. This is counterproductive in modern farming, where efficiency is crucial to survival. Thin wall driplines can lead to significant cost savings when some heavy wall attributes are no longer crucial to farming success.
Thin wall driplines are also the perfect solution in circumstances where a producer may not have the capital outlay for the intended or preferred heavier wall dripline. A lower cost thinner wall can be used initially and upgraded to a heavy wall later once the crop brings in sufficient income.
Yet users of thin wall driplines would know that in-field dripline damage becomes a significant challenge. Producers do not have the time to treat driplines with kid gloves. In the field, you need irrigation equipment that does the job and survives tough conditions.
The toughest thin wall dripline ever made
In response to this challenge, Netafim developed an extremely robust thin wall dripline that still upholds the high level of efficiency of Netafim products. The aim was to create a durable dripline and to reduce the damage that occurs when driplines are installed or retrieved. Enter Streamline™ X, the toughest dripline ever made.
The Streamline™ X concept is simple. Just like cars have bumpers that protect their chassis from being damaged, this new dripline is shielded by external and internal ribs that act as a barrier between the ground and the pipe, and protect the dripline from installation-related cuts and tears. The product was introduced to the market in 2019.
Dripline comparisons
Irrigation designers and farmers alike face myriad dripline options with various specifications and technical data. Comparing similar products and selecting the right product type and brand for the conditions at hand can be a challenge. This can be made somewhat easier by understanding the impact of and interaction between certain engineering features that affect the efficiency and durability of a dripper.
Remember, a dripper needs to reduce its inlet pressure from 1 to 0 bar and get 1ℓ/h through it. A complicated mathematical equation explains the pressure difference from the inlet of the dripper flow path to the outlet. However, all we need to understand is that the pressure difference comprises two aspects: turbulence and friction loss.
Pressure loss = turbulence + friction loss
It is essential to understand the interaction between these two aspects. The less turbulence the dripper can create, the more it must resort to friction loss to create the necessary pressure loss. Friction loss does not contribute to keeping a dripper clean. However, the higher the turbulence and turbulence coefficient, the better the dripper is at keeping clean. A good-quality dripper emits a predetermined flow rate that is accurate and constant over its intended lifespan. To achieve this goal of efficiency, a dripper must be kept clean.
A few engineering features contribute to a higher turbulence coefficient:
- Turbulence coefficient – higher is better.
- Number of teeth – fewer is better.
- Flow path length – shorter is better.
- Flow path depth – deeper is better.
- Flow path width – wider is better.
The other important contributing factor to a dripper’s ability to stay clean is the size of the effective filtration area. The larger the filtration area the better, as it contributes to clogging resistance and will take longer to get contaminated.
Both sides of the coin
The toughness of Streamline™ X can be attributed to the longevity of the dripper on the one hand and the durability of the dripline on the other. Therefore, both dripline and dripper characteristics were put to the test when the Netafim product management team tested and compared Streamline™ X against two competing thin wall driplines.
Choose excellence, choose quality
It is vital not to veer from quality when moving to the lower range of drippers and driplines. It remains important to scrutinise the specifications shared on dripline packaging and determine which dripline you can rely on in the field.
Look for a product that offers guaranteed longevity and is designed and manufactured with the explicit goal of decreasing clogging risk, as well as delivering water uniformly and efficiently. Dripline selection boils down to selecting the correct product for the crop and circumstances, a quality product that can do the job at hand in difficult conditions and that will offer the best return on investment. – Jerry Austen, Product Manager, Netafim South Africa